The present invention relates to memories, and, for example, to effective technology to be utilized in a semiconductor integrated circuit device such as a buffer memory used in data transmission.
In a dynamic type RAM (random access memory) or a static type RAM, memory access is performed in synchronization with an external signal such as substantial chip selective signal and address signal. Regarding such dynamic type RAM or static type RAM, description is, for example, in "Hitachi IC memory data book" published by Hitachi, Ltd. in September 1985.
In the above-mentioned dynamic type RAM or static type RAM, the memory access speed is restricted by the external signal as above described. Consequently, when the memory access is performed from a microprocessor or the like with different memory access speed, the bit rate is determined by slower operation speed.